A. Field of the Invention
The invention relates to a Contact Image Sensor (CIS) scanner, especially to a scanner having a universal Contact Image Sensor (CIS) carriage for adapting to guiding devices of various structures, thereby to simplify the inner structure of the scanner.
B. Description of the Prior Art
The advantages of applying a CIS module in a flatbed scanner have been considered as a solution for simplifying the structure for a low-end scanner. A new approach intends to replace a CCD line image sensor with a CIS contact sensor for low-end scanners because a CIS module is compact and easy to install. The CIS module contains all the optical members, such as light source, mirrors, and photoelectric converting device in a bar-shaped module. Since the CIS module can be manufactured and purchased from the third party, the job of trouble-shooting and installation will be much easier than a conventional CCD line sensor. Nevertheless, this new approach did not prevail because there is no breakthrough on the structure of a flatbed scanner yet to overcome the problem of short scene depth of a CIS module. It is known that the scene depth of a CIS module is only about 0.3 mm. It will be very easy for the sheet to shift away from its scene depth if manufacturing errors or distortions are not avoidable.